Enzymatic detergent bar

ABSTRACT

AN ENZYMATIC DETERGENT BAR, ESPECIALLY USEFUL FOR WASHING LAUNDRY AND REMOVING STAINS THEREFRM, COMPRISES: A SYNTHETIC ORGANIC DETERGENT, E.G., LINEAR HIGHER ALKYL ARYL SULFONATE; AN ENZYME, E.G., A PROTEASE; A BUILDER OR FILTER SALT, E.G., ALKALI METAL CARBONATE, ALKALI METAL SULFATE; A BINDER, E.G., CORN STARCH; AND WATER, IN SUCH PROPORTIONS AS RESULT IN PRODUCTION OF A FORM-RETAINING, HRD, NONTACKY, READILY SOLUBLE AND EFFECTIVELY CLEANING BAR. ALSO DISCLOSED ARE METHODS FOR MAKING AND USING THE DESCRIBED DETERGENT BAR.

United States Patent 3,798,181 ENZYMATIC DETERGENT BAR Salvador MorelosVazquez, Atzcapotzalco, Mexico City, Mexico, assiguor toColgate-Palmolive Company, New York, N.Y. No Drawing. Filed Nov. 3,1970, Ser. No. 86,594 Int. Cl. Clld 3/38, 17/00 US. Cl. 252-539 ClaimsABSTRACT OF THE DISCLOSURE An enzymatic detergent bar, especially usefulfor washing laundry and removing stains therefrom, comprises: asynthetic organic detergent, e.g., linear higher alkyl aryl sulfonate;an enzyme, e.g., a protease; a builder or filter salt, e.g., alkalimetal carbonate, alkali metal sulfate; a binder, e.g., corn starch; andwater, in such proportions as result in production of a form-retaining,hard, nontacky, readily soluble and effectively cleaning bar.

Also disclosed are methods for making and using the described detergentbar.

SUBJECT OF THE INVENTION This invention relates to a detergent barintended primarily for use in laundering applications. Moreparticularly, the invention is of a detergent bar containing an enzymeor a mixture of enzymes useful to chemically convert hard-to-removestains on natural or artificial fabric materials to a more readilyremovable form, so that they can be washed out in a launderingoperation.

Also within the invention are processes for manufacturing suchenzyme-containing detergent bars and methods for using them to washstained laundry.

BACKGROUND OF THE INVENTION The production of synthetic detergents inthe last forty years has increased sharply and such materials have beendeveloped to a point where they wash exceptionally well, so that nowsoap is becoming outmoded or is rarely used for heavy duty laundering ofclothing and other soiled articles. However, it has been found that thesynthetic detergents, even in highly built formulations containingvarious additives such as peptizing agents, anti-redeposition compoundsand strongly alkaline builders, do not completely remove various stainswhich set into the fabrics of the laundered items. Accordingly,solvents, oxidizing and reducing agents, and more recently, enzymes havebeen included in built synthetic detergent powders and it has been foundthat in the wash water the enzymes chemically attack various stains,breaking them down into more easily removable compounds. Theeffectiveness of enzymes in performing this function is evidenced by thelarge number of commercial detergent powders and pre-soak compositionswhich now contain them and the acceptances of such products byconsumers.

The high activities of enzymes, which act as catalysts for variousbiological or chemical reactions, are shown in the use ofenzyme-containing built synthetic detergent powders in automatic washingmachines. In such machines, which generally hold from 9 to 18 gallons ofwash water, the weight of washing powder employed is usually from one toeight ounces or from about 30 to 225 grams. Thus, the concentration ofenzyme in wash water, even at a 1% concentration in the detergentpowder, would be on the order of 0.001 to 0.004% and of course, for thelesser quantities of enzyme often' employed, the concentration is evenlower. Similarly, the concentrations of active cleaning agents in suchdilute washing solutions are low, although usually many times as greatas the enzyme concentration.

3,798,181 Patented Mar. 19, 1974 Although enzymes have significantstain-removing properties, they also possess certain disadvantageouscharacteristics which have hitherto limited their use in variousproducts where they could be functionally important. For example, in thepresence of moisture and/or other materials with which the enzymes maybe reactive, it has been found that malodorous by-products are produced.The enzymes themselves are often of an aesthetically unpleasant odor andtherefore, they are limited in their applications in cosmetics and otherproducts intended for application to the human body or even for handlingduring use. They also lose their activity on storage in the presence ofmoisture or reactive materials.

Detergent bars, usually containing a synthetic organic detergent and aninorganic builder or filler salt, have been produced for use as laundrybars and in some cases, have been employed as toilet soaps, for use withsea water or other extremely hard waters. Among the inorganic salts usedin such bars have been the alkali metal silicates, phosphates,carbonates and sulfates and among the synthetic detergents have been theanionic alkyl benzene sulfonates. Gums and gelling agents have beenemployed as binders in detergent bars and starches have been added asbinders or fillers.

DESCRIPTION OF THE INVENTION Although the various components of thepresently invented bars are known ingredients of different detergentcompositions and products, they had previously not been combined in adetergent bar like that of the present invention and the specialadvantages of such bar and its use had not previously been obtained.

In accordance with the present invention there is provided anenzyme-containing detergent bar which comprises effective proportions ofan enzyme for chemically converting hard to remove soil and stains to amore readily removable form, a synthetic organic detergent, a buildersalt or a filler salt for said detergent, a binding agent formaintaining the detergent, builder or filler salt and enzyme in cohesivebar form, and water, all homogeneously combined in a form retaining,hard, non-tacky, readily soluble, eifective cleaning bar. Preferably,this bar is based on a linear higher alkyl aryl sulfonate detergent,alkali metal carbonate, corn starch, protease and moisture, each withinthe ranges of proportions described later herein. Also within theinvention is a method of manufacturing such detergent bars in which thevarious components are mixed together at an elevated temperature, whichmay be obtained from a reaction of some of the ingredients, the enzymeis admixed with the rest of the composition at a lower temperature andthe total mixture is milled, plodded and pressed into bars. Also claimedas part of this invention are novel processes for-use of enzymaticdetergent bars wherein wet laundry is rubbed with the detergent bars atdirty or stained spots, soaked in wash water containing dissolvedmaterials from the bar and subsequently agitated in such wash water orother detergent solution.

The invented detergent bars are sufficiently hard so as to be maintainedin a solid form resembling soap, and yet, despite the inclusion of verysoluble components, do not dissolve too readily and do not become softor mushy after use, due to gelation with water. The enzyme component,although in the presence of a significant proportion of water in thebar, which helps to maintain the component in homogeneous form andprevents crystallizing out into hard kernels of the less solubleingredients, does not decompose, and useful enzymatic action is obtainedeven after lengthy storage periods and after storage at hightemperatures and high humidities. The enzymes used do not discolor thebar objectionably on storage and do not become malodorous. In fact, theyeven seem to improve the bouquets of perfumes employed. Such results areattributed in part, at least, to the binder employed, especially cornstarch, which seems to have a stabilizing effect upon the enzymes, inaddition to its water-holding, binding, filling and slip-improvingeffects on the bar product. When significant amounts of fluorescentbrighteners are present, they additionally help to improve theappearance of the washed previously stained laundry, by brightening 1tand thereby making the effects of any small amount of staming materialstill present after laundering less noticeable. Of course, thedetergent, builder and filler constituents all perform their desiredfunctions in the presence of the other ingredients. Of the detergents,it is preferred to employ linear alkyl aryl sulfonates, which wash verywell 1n the presence of the other constituents and also are relativelyeasily biodegradable. Although phosphates are excellent builders, forWater pollution control purposes it may be desirable to replace themwith the carbonates, bicarbonates and silicates, as is done in thepreferred formulas illustrated herein.

The invented detergent bars are easily manufactured with conventionalequipment and may be made directly from detergent acid and soda ash (toform the active detergent ingredient), with addition of the variousother constituents, followed by conventional milling, plodding andpressing operations. In use, the products are preferably employed insuch a manner that advantage is taken of soaking the soiled and/orstained laundry in a solution of the detergent bar materials, so as totake advantage of then enzymatic action.

The synthetic organic detergent employed may be any suitable suchmaterial, including anionic, nonionic or amphoteric detergents and insome cases, cationics may also be employed, although they will usuallybe avoided when anionics are present. Of the detergents, it is preferredto employ those which are anionic and of these the sulfonated andsulfated (sulf(on)ated) detergents, preferably having an alkyl group offrom 8 to 22 carbon atoms, have been found to be best for a desiredcombination of cleaning effect and best physical characteristics.

The sulfonic or sulfuric group of the anionic sulf(on)- ated detergentsmay be joined directly or indirectly to a hydrophobic organic group,which usually contains the mentioned higher alkyl. Among the watersoluble anionic sulfonated detergents the higher alkyl aryl sulfonateshaving about 8 to 18, preferably 10 to 16 carbon atoms in the alkylgroup are particularly effective. It is preferred to use the higheralkyl benzene sulfonate detergents, although analogous materialscontaining mononuclear aryl groups such as xylene, toluene or phenol,may be employed instead of the benzene nucleus. The higher alkylsubstituent may be either straight-chained or branched to produce thedesired products. The straight-chained materials include those in whichthe alkyl groups are n-decyl, n-dodecyl, ntetradecyl and n-hexadecyl,which formerly were derived exclusively from natural fatty material butnow may also be obtained from petroleum. The straight chained or linearalkyl benzene sulfonates are comparatively easily biodegradable, whereasbranched chain materials are more difficult to degrade biologically andwill often be avoided where water pollution is a problem. However, wherebranched chain alkyl aryl sulfonates and other detergents containingbranched lipophilic groups are usable, they perform very satisfactorilyin the present detergent bars, being excellent cleaning agents andpossessing the desired physical characteristics for making a good bar.Even in this respect, however, it has been found that the detergentscontaining linear higher alkyl substituents are generally firmer andmake a more satisfactory detergent bar of good physical characteristics.In addition to the alkyl aryl sulfonates, the other anionic sulf(on)ateddetergents may be employed, such as the higher alkane sulfonates(higher=8 to 22 carbon atoms in the alkyl group), the higher alkylsulfates, the higher alkene sulfonates,

higher alkene sulfates, the higher alkyl sulfonates wherein the alkylgroup is linked to sulfonic acid group through a COOR group (R being alower alkyl or a substituted lower alkyl group of 2 to 3 carbon atoms),and analogous types of compounds wherein the linking is through a CONHRgroup or other suitable intermediate radical. The useful sulfatesinclude the alkyl oxyethylene sulfates, the monoglyceride sulfates, thesulfated higher alkyl phenyl oxyethylene ethanols or polyoxyethyleneethanols and the sulfated polyoxyethylene ethanols or sulfatedpoly-lower oxyalkylene lower alkanols. These are only a few of theanionic detergents known in the art to be useful solid or solidifiablecleaning agents and which can be incorporated as the principal syntheticorganic detergents in the present compositions. Similarly, phosphorusanalogues of the above compounds are useful in at least partialreplacement of the sulf(on)ated materials.

Among the nonionics, as with the anionic compounds, it is preferred toemploy those detergents which are normally solid and water soluble.Included within this group are higher alkyl aryl phenol polyoxy-loweralkylene lower alkanols, polyoxylower alkylene alkanols, higher fattyalcohol ethers of polyoxy-lower alkanols, block copolymers of differentpolyoxy-lower alkylene alkanols, and the heterocyclic mixedpolyoxy-lower alkylene alkanols. In such compounds, the lower alkylenesare usually of 2 to 4 carbon atoms. The alkanol portion of the molecule,in some cases, may be terminated with a lower alkoxy group, in-

stead of a free hydroxyl.

The amphoteric or ampholytic detergents, although not preferred majorconstituents of the present synthetic detergent component, are usefulmainly as partial replacements or supplements for anionic and nonionicdetergents. These include the betaines, sulfobetaines, Miranols,amidobetaines, and amidosulfobetaines. The cationic compounds includeprincipally the quarternary ammonium halides but analogous phosphoruscompounds may also be employed. Substituents on the nitrogen willnormally be lower alkyl, higher alkyl, benzyl or aryl, in variouscombinations.

The synthetic detergents of the anionic type will usually be employed astheir water soluble salts, with the saltforming ion preferably being analkali metal, e.g., sodium, potassium. However, other salt forming ionsmay also be employed, such as ammonium, lower alkanolamine and loweralkylamine. For the cationics, the salt-forming ion will usually behalide, e.g., chloride, bromide 01' iodide.

Some specific examples of useful detergents which may be used ascleaning agents in the present bars are sodium n-dodecyl benzenesulfonate; sodium n-tridecyl benzene sulfonate; potassium n-hexadecylbenzene sulfonate; sodium n-dodecyl toluene sulfonate; sodium propylenetetramer benzene sulfonate; sodium propylene pentamer benzene sulfonate;sodium tridecyl benzene sulfonate, wherein the tridecyl is a mixture ofpropylene pentamer and propylene tetramer; sodium butylene trimerbenzene sulfonate; potassium tridecyl benzene sulfonate; sodium laurylsulfate; sodium lauryl sulfonate; ammonium coconut oil fatty acidsmonoglyceride sulfate; triethanolamine n-hexyl sulfonate; sodiumN-lauroyl sarcosine; sodium oleoyl isethionate; sodium lauroyl N-methyltauride; dodecyl glycerol ether sulfonate; sodium lauryltri(oxyethylene) sulfate; nonyl phenol hexa(oxyethylene) sulfate; lauryldeca(oxyethylene) ethanol; block copolymers of ethylene oxide andpropylene oxide, having a molecular weight of about 3,000 (Pluronics);various Miranol detergents, described at pp. 142-144 of Detergents andEmulsifiers (McCutcheon), 1969 Annual; benzothonium chloride; dimethyldibenzyl ammonium chloride and cetyl trimethyl ammonium bromide.Descriptions of other such detergents are found in the text SyntheticDetergents by Schwartz, Perry and Berch, published in 1958 by Inter=science Publishers, New York, pp- 25-143.

The builder salts which are useful in making the present bars includethe conventional builders for synthetic organic detergents but of these,it is preferred to employ, at least in part, the alkali metal carbonatesand/or bicarbonates. The use of such builder(s) facilitates aneconomical manufacturing process wherein an anionic detergent acid isneutralized in situ. However, in addition to the carbonates andbicarbonates, there may be employed various boron-containing builders,e.g., borax; silicates, such as those having an Na O:SiO ratio of from1:1 to 1:3, preferably from 1:1.6 to 112.35; and phosphates, especiallythe polyphosphates e.g., pentasodium tripolyphosphate and tetrapotassiumpyrophosphate. Also useful are the organic builders, which are usuallyemployed to a lesser extent than the inorganic builders. Exemplary ofthese are NTA (trisodium nitrilotriacetate monohydrate) and EDTA(ethylene diamine tetraacetic acid, usually used as the tetrasodium,tetrapotassium or trisodium salt).

Filler salts, generally water soluble inorganic salts which add bulk tothe detergent bar and sometimes desirably modify its solubility andphysical characteristics, include the water soluble inorganic sulfatesand bisulfates, plus other suitable water soluble salts which may beemployed on occasion, e.g., sodium chloride. The filler and buildersalts may be anhydrous or hydrates. The fillers will often be present asbyproducts from the manufacture of anionic detergents, etc.

Binding agents for holding the bar together in a cohesive, yet desirablysoluble form, include the natural and synthetic starches, gums andthickeners and derivatives thereof. Thus various starches such as cornstarch, potato starch, yucca starch, tapioca starch and starches derivedfrom cellulose are useful binders, as are the components and derivativesthereof, such as amylose, amylopectin and partially hydrolyzed starches.The starch may be at least partially replaced by cereal flours whichcontain large proportions of it, such as wheat or potato flours. Gumsinclude alginates, agar agar, guar and mucilages. Some binder compoundsalso possess soil-suspending properties and help to maintain the removeddirt in finely divided suspension in the wash water to prevent it fromre-adhering to the laundered material. Among such materials arepolyvinyl alcohol and sodium carboxymethyl cellulose. Although cornstarch does not have as significant an effect as the PVA or CMC, aspreviously mentioned, it is the most preferred binder in the presentbars, principally because it forms a bar with desired tactileproperties, low density (compared to other detergent bars containinginorganic salts), desired solubility and smoothness, and, mostimportant, it aids in stabilizing the enzymes, preventing theirdegradation and consequent inactivation and the development ofmalodorous byproducts. Various corn starches appear to have this desiredproperty, over a variety of amylopectinzamylose content ratios.

The enzyme constituent of the detergent bar is most preferably aproteolytic enzyme. Such enzymes are active on proteinaceous materialsand catalyze digestion or degradation of such matter when it is presentin the form of a stain on a fabric. The degradation by a hydrolysismechanism, for example, results in the production of a more solublematerial which is removable by the built synthetic detergent solution.The various enzymes employed are generally effective at pH rangesregulated by the content of builder salt in the detergent bar. Such arange may be from about 4 to 12 and is preferably about 8 to 11. Theproteolytic enzymes, although subject to some degradation by heat, maybe employed in washing solutions at temperatures up to about 80 C. andare also effective at low temperatures, down to about 10 C. Among theproteolytic enzymes may be mentioned pepsin, trypsin, chymostrypsin,papain, bromelain, collagenase, keratinase, carboxylase, aminopeptidase, elastase, subtilisin and aspergillopepidases A and B.Preferred enzymes are subtilisin enzymes manufactured and cultivatedfrom special strains of spore forming bacteria, particularly Bacillussubtilis.

Proteolytic enzymes such as Alcalase, Maxatase, Protease AP, ProteaseATP 40, Protease ATP 120, Protease L-252 and Protease L-423 are amongthose enzymes derived from strains of spore forming bacilli, such asBacillus subtilis. Different proteolytic enzymes have different degreesof effectiveness in aiding in the removal of stains from textiles andlinen. Particularly preferred as stain removing enzymes are subtilisinenzymes. Metalloproteases which contain divalent ions such as calcium,magnesium or zinc bound to their protein chains are of interest. Themanufacture of proteolytic enzyme concentrates is described in GermanOffenlegenschrift 1,800,508 and Dutch patent application 6815944.

Instead of or in partial replacement of the proteolytic enzyme, otherenzymes may also be used, usually for specific purposes. Thus, anamylase may be employed, e.g., bacterial amylase of the alpha type suchas is obtained by fermentation of Bacillus subtilis. Among the otherenzymes that may be used are those characterized as hydrolytic,lipolytic, oxidizing, reducing and glycolytic. Such include catalase,lipase, rnaltase and phosphatase. The mentioned enzymes and classesthereof, while considered to be most useful, are not the only effectiveones in the present bars. Virtually any enzymes that contribute toloosening of the bond by which soils or stains are held to fibriousmaterials may be used in the bar formulas. Guides to such use may befound in Principles of Biochemistry by White, Handler, Smith and Stetten(1954).

The contents of particular enzymes are often measured by theiractivities in standard tests. Thus, the activities of proteolyticenzymes may be measured by Anson units and that of amylase by Novoalpha-amylase units. The number of Anson units of a highly preferable,commercially available subtilisin enzyme, such as Alcalase, produced byNovo Industri A/ S, Copenhagen, Denmark, is l-4/ g. and Anson ratings ofstarting materials up to about 8/g. are possible. Such enzymes,generally in the form of finely divided powders, beads or prills, may bedistributed on a carrier or may be substantially salt-free. Whenemployed, the carrier will often be calcium phosphate, sodium sulfate,sodium chloride or other suitable soluble or insoluble salt or othermaterial, often depending on the product in which the enzyme is to beincorporated. Of course, as with other components of the presentdetergent bars, mixtures may be used to obtain most desired results.

The water which is a part of the final bar product is obtainable as asolvent with various constituents or as water of hydration accompanyingthem. If more water is needed to make the product sufficiently plasticto be worked, it may be supplied as an additional ingredient, in whichcase it is preferred to utilize deionized water. Nevertheless, in someinstances, as when the detergent employed foams and washes better in thepresence of hardness ions, harder waters, up to about 300 parts permillion but usually of a hardness no greater than about parts permillion and preferably less than 60 p.p.m., as calcium carbonate, may beused.

The perfumes employed in the present bars may be selected from a widevariety of perfume materials previously found useful in soaps anddetergents. They include aromatic, sweet, citric, floral, fragrant,ethereal, esteric, resinous, camphoric and heavy perfumes.Representative perfumes of such types include lemon oil, oil ofduenella, citral, pine oil, non-aldehyde, oil of Bergamot, rose hip oil,lemongrass oil, terpineol, menthol, coumarin, eugenol, oil of pepermint,etc., and various fixatives which may be employed with these. It appearsthat the presence of the enzyme helps to improve the stability of theperfumes, possibly by causing the destruction of proteinaceous and othermaterials which could otherwise catalyze reactions of the perfumes. Thisstabilization effect is particularly pronounced with respect to citrusoils, oil of citronella, and proteolytic enzymes.

The fluorescent brighteners which greatly improve the appearance ofwashed, previously stained laundry items, may be any of the wide varietyof such materials, also known as optical bleaches, optical brightenersand fluorescent whiteners. included among these are brightenersspecifically useful for whitening cotton, such as the CC/ DASbrighteners which are derived from the reaction be utilized as thecorresponding acids, subsequently to be converted to salt form. They maybe used essentially pure or on carriers. Cotton brighteners will usuallycomprise a major proportion of the brightener system employed and suchsystem will generally also include an amide-polyester brightener. Amongthe brighteners usable in the present bars are Calcofluor White ALF(American Cyanamid); ALF-N (American Cyanamid); SO-F A- 2001 (Ciba); CWD(Hilton-Davis); Phorwite :RKH (Verona); CSL, powder, acid (AmericanCyanamid); CSL, liquid, monoethanolamine salt (American Cyanamid); PE766 (Verona); Blancophor PD (GAF) UNPA (Geigy); Tinopal RBS (Geigy); andRES 200 (Geigy). A good description of the optical brighteners is foundin Optical Brighteners and Their Evaluation, by Per S. Stensby, areprint of articles published in Soap and Chemical Specialties in April,May, July, August and September 1967, especially at pp. 3-5 thereof.

In addition to the required constituents of these bars, variousadjuvants may be present to give them additional desired properties,either of functional or aesthetic nature. Thus, there may be included inthe bars pH adjusting agents, e.g., sodium hydroxide, triethanolamine,sulfuric acid; buffering agents, e.g., sodium borate, sodium bisulfate;foam improvers, e.g., lauric myristic diethanolamide, lauryldimethylamine oxide; bactericides, e.g., tetrachlorosalicylanilides,hexachlorophene; fungicides; dyes; pigments (water dispersible);preservatives; ultraviolet absorbers; fabric softeners, and bleaches,e.g., sodium perborate. Of course, in the selections of the ad juvantsto be employed, they will be chosen so as to be compatible with the mainconstituents of the bars.

The proportions of the components of the detergent bar are maintained soas to produce an effective cleaning or laundry bar with good enzymaticaction and of desired physical properties. Thus, within the descriptionin the specification and the proportions mentioned herein, adjustmentswill be made depending on the particular characteristics most desired inthe product.

The synthetic organic detergent will be from 10 to 40% of the bar inalmost all situations and will preferably be from 20 to 40% thereof, themost preferable concentration being about to 35% of the final product.It has been found that such proportions result in effective cleaning andoften help to maintain the homogeneity of the bar product, inconjunction with the binder andwater constituents. As has beenmentioned, the preferred alkyl benzene sulfonate detergent is usually amajor proportion of the detergent constituent. Preferably, it comprisesfrom 70 to 100% thereof. With it may be included other anionic, nonionicor ampholytic detergents, and sometimes, even cationic materials. Thealkyl benzene sulfonate may be completely replaced, in some instances,by other anionic or nonionic detergents and may be replaced in minorproportion by the ordinary higher fatty acid soaps which, strictlyspeaking, are not synthetic organic detergents within the usual meaningof that term.

The builder and filler salts will ordinarily be from 20 to 60% of thebar and preferably, a major proportion of the total of filler andbuilder will be builder. Depending on the types of builders and fillersemployed, the contents thereof in the products may be near the bottom ortop of this range. Thus, a preferred range is from 25 to 55% of buildersalt, with any remaining materials being filler. Of the builders, it isgenerally desirable to have from about 5 to 25% of sodium carbonate,from about 5 to 40% of sodium bicarbonate, and 0 to 10% of sodiumsilicate, with 0 to 3% of sodium sulfate and from 0 to 2% of pentasodiumtripolyphosphate or tetrasodium pyrophosphate also being present.

Usually, at least about 0.5% of each of the builders or fillers will bepresent, it they are employed, because lesser amounts appear to have nouseful activity.

The binder constituent will generally comprise from 5 to 40% of thedetergent bar, preferably from 10 to 35% thereof. This will usuallyinclude a major proportion of starch, preferably from 70 to thereof andmost preferably, it will be entirely corn starch. Other binders of thetypes previously mentioned may be employed to supplement the elfects ofthe starch in the product.

The enzyme, as a concentrated commercial form thereof, may be from 0.05to 5% of the bar. However, because of cost and functionalconsiderations, this proportion will normally be 0.1 or 0.2 to -1% ofthe product, which proportion has been found to be commerciallycompetitive and yet, sufiiciently active to improve the stain-removingproperties of the bar significantly. Preferably, the entire proportionof the enzyme concentration will be protease or other useful proteolyticenzyme, because the proteinaceous stains appear to be those which aremore common and most difficult to remove. Thus, of the enzyme charge, amajor proportion, preferably from 70 to 100%, will be proteolytic enzymeor protease. If the enzyme is present on a carrier, the percentage willbe adjusted accordingly. In terms of Anson units, the proportion ofenzyme in the detergent bar will be such as to result in from about0.001 to 0.1 Anson unit per gram of bar.

The moisture content of the milled, plodded and pressed detergent barswill usually be within the range of from 5 to 25% thereof. Such a widerange of moisture contents is useful because some of the builder andfiller salts are hydratable and moisture is taken up by the corn starchor other binder. Normally, the moisture content will be within the 8 to22% range and preferably it is from 10 or 12 to 17%. Such a moisturecontent allows the bar to be processed easily, gives it desiredsolubility characteristics and promotes homogeneity in manufacture.

The fluorescent brightener content usually will be from about 0.05 to 2%of the bar and will preferably be from about 0.1 to 0.5% thereof. Amajor proportion of the fluorescent brightener content will often becotton brightening compound, with a minor proportion thereof beinguseful in brightening nylons and polyesters.

The content of perfume, while also minor, is very important to theaesthetic acceptance of a detergent bar. It will usually be from 0.1 to2% of the bar, preferably 0.1 to 1% thereof and in some preferredenzymatic bars a major proportion of the perfume will be a citrus oil oroil of citronella. Stabilizer materials in the products, pigments,soluble or insoluble; dyes; foaming agents; solvents; bufiers; and anyother adjuvants which may be employed, will usually be limited to 10% ofthe bar, preferably 5% and most preferably 3% thereof. Individualadditive constituents will normally not exceed 5% of the bar and willgenerally be maintained at a level less than 1% thereof.

The detergent bar produced will usually be comparatively light, whenjudged against Other inorganic salt-built competitive products. Thus,the density will ordinarily range from about 1.2 to 1.5 grams per cubiccentimeter. The pH of a 1% solution of the bar will usually be in therange of from 7 to 11 and is preferably from 8 to 10. In wash water orsoaking solution, the pH may drop about one unit. It will usually bedesired to maintain the pH at a range at which the particular enzyme anddetergents employed are most effective.

To manufacture the detergent bars the various constituents may beadmixed in any suitable order. A sigma blade mixer is a suitable medium,especially where a subsequent drying operation is desirably avoided, asin the case of heat-sensitive enzymes. To avoid such need for heatingthe final composition, a dry process of manufacture is found to be mostefiicient, especially when anionic synthetic organic detergent salts areemployed. For example, in the case of alkyl benzene sulfonates, theremay be used the corresponding detergent acid, usually in aqueoussolution, and it may be dry neutralized with sodium carbonate or sodiumbicarbonate powder or sodium hydroxide or other suitable agent.Preferably, the neutralizing agent, e.g., sodium carbonate, is employedin excess, so that some of it will be converted to the bicarbonate andsome will not be consumed in the neutralization reaction, therebyserving as the desired builder salt in the composition. Heat isgenerated in the neutralization reaction, even when a cooling jacket isemployed, and the temperature often rises to about 50 C. and sometimes,above 55 C. Such temperatures are harmful to many enzymes and other heatsensitive ingredients of the composition, so the mixture of theneutralized detergent salt, binder, builder and/ or filler and water iscooled to a temperature of 45 C. or below, preferably to below 35 C., atwhich temperatures the enzyme and other heat sensitive materials, suchas perfumes and dyes, are added. The proportions of the variousingredients were previously given and will not be repeated here. Aftergood mixing in the sigma blade mixer or other equivalent apparatus, themix is dropped to a conventional soap line, wherein it is milled tochip, usually from 0.002 to 0.015 inch thick, which is plodded in astandard ploddler with heat on the nozzle plate, to produce a bar whichis then cut to length and pressed in a conventional soap press, usuallyat a pressure of from 25 to 500 lbs/sq. in. In a modification of thisprocedure, to produce attractively colored or speckled bars, coloredmaterial, i.e., dyed pentasodium tripolyphosphate granules or beads, maybe blended in with the composition paste or with milled chips. This isdone so as to prevent complete distribution of the color throughout thebar and leave it with a speckled or marbelized appearance. Generally, insuch procedure, the weight of colored particles added to the paste willbe from 0.2 to thereof, preferably from 0.5 to 2%. It is considered thatthe main area of manufacturing process novelty in the invention residesin the use of the dry neutralization process in the making of anenzymatic detergent bar, with cooling to protect the enzyme. Consequently, since the various other steps in the method invol-veconventional equipment and processing conditions (milling, plodding andpressing), these are not recited in detail here. Of course, it is clearthat orders of additions of materials may be varied, other adjuvants maybe included, constituents may be added as solids, suspensions orsolutions, etc., without departing from the procedures of the invention.

Enzymatic detergent bars are especially useful for removing stains anddeeply worked-in dirt from clothing and other items of laundry. Ofcourse, the particular detergent bar formula that will be employed mayhave the enzyme chosen so as to have greatest activity at the pHemployed and against the stains encountered. Thus, with respect to dyestains, oxidative or reductive enzymes may be used whereas with fruitstains, which may be carbohydrate-based, enzymes which attack the largercarbohydrate molecules may be most successful. However,

although it is known to vary the enzyme employed with the type of stainbeing removed, it has been found that with the present bars theproteolytic enzymes seem to be effective against a wide variety ofstaining materials, perhaps due to a proteinaceous link in theaflixation mechanism by which the stain is held to a substrate, whetherthat substrate be cotton or synthetic, such as polyester or nylon. Infurther discussion, for simplicity, reference will be made mostly toproteolytic enzymatic bars.

The laundry is initially moistened or wet, preferably by immersion in atub of water, after which it is drained and the bar is rubbed by handagainst the most badly soiled areas, e.g., shirt collars, cuffs, trouserknees, and on stained surfaces. The stains to which the bar may beapplied are, for example, food stains such as chocolate, cherry,blueberry, grape, blood, gravy, ketchup, mustard, wine and grease, butalso removed are grass stains, inks, etc. Normally the stains will nothave to be rubbed for more than seconds and rarely is this necessary formore than one minute. After rubbing of all the stains of a particularitem of laundry, it may be left in that wet condition to enable theenzyme to work on the stain or, if desired, the laundry may be placed ina tub with more water, allowing the dissolved detergent bar constituentsto contact the entire area of the laundry, although in a more dilutestate. Generally, the concentration of detergent bar materials in thesoak water will be from 0.05 to about 1.0% and the soaking period willbe from about /2 hour to 10 hours but it may be as long as 24 hours oreven more. Normally, the enzymes are effective for only about 2 to 10hours, but even so, additional soaking allows the combination ofdetergent and builder better to loosen the partially broken down stain.The temperature of the soak water will usually be about room temperatureor slightly higher although temperatures within the range of 2060 C. areuseful. Normally, however, the temperature will be from 20 C. to 40 C.At the temperatures and over the times indicated, the binder or cornstarch component of the enzymatic bar performs a useful function intending to coat the item being soaked when the laundry is not placedinto a dilute bath, preventing it from drying out excessively, whichcould inactivate the enzyme.

After completion of the soaking period, a dilute solution of the applieddetergent bar materials may be formed and washing of the laundry may beconducted in this solution, generally at an elevated temperature of from50 to 90 C. although preferably at a temperature of 50 to C. In somecases, colder water, at a temperature as low as 15 C., can be employed.If the enzyme has become inactivated, additional detergent bar or otherenzymatic and detergent materials may be added to the wash water. Thesubsequent washing may be in an automatic washing machine for a periodof from five minutes to one hour or may be by hand and may take asimilar or shorter time. After completion of washing, the laundry isrinsed, wrung out and dried. If, after washing is finished, any stainsare still noted on the laundry, they may be rubbed with the detergentbar and, if desirable, may be soaked again.

The results of the washing procedures described are surprisingly good.Despite the fact that the detergent bar may have withstood lengthyperiods of storage, up to six months and such storage may have been at ahigh temperature and under high humidity, with the bar containing asubstantial proportion of moisture, the enzyme is still active and thebar color is good. Furthermore, the perfume is truer than in barswithout enzyme. Thus, by the present invention, there is produced aproduct which is needed in the laundry to supplement the granularenzymatic materials now available and to perform a function for whichthe granular products are not suited. The invention is a surprising onebecause the expectedly incompatible constituents of the product do notdestroy each other and, on the contrary, result in the creation of ahighly useful and hitherto unavailable detergent product and anetfective washing and stain-removing process. Such products are usefulwhere Washing machines are not available and hand washing is standardpractice but they are also employable in conjunction with machinewashing to improve washing and stain removal.

The following examples illustrate the invention. Unless otherwisespecified, all parts given are by weight and all temperatures are indegrees centigrade.

EXAMPLE 1 Percent Bleached higher alkyl benzene sulfonic acid (95%aqueous solution, higher alkyl-tetrapropylene) 33.3 Soda ash, finelydivided (90% passes through a 140 mesh sieve, US. Standard Sieve Series)27.3 Corn starch 29.6 Water 8.1 Sodium bisulfite, powder 0.6 ProteaseAlcalase enzyme (Novo Industries, 1.5

Anson units per gram minimum activity) 0.6 Titanium dioxide, anatase 0.3Perfume, Rondelia detergent type 0.2

In a sigma blade mixer the detergent acid is admixed with soda ash inthe presence of a suflicient small proportion of water to aid in theneutralization reaction. Although a cooling jacket is employed, the heatof reaction raises the temperature to about 65 C. After substantialcompletion of neutralization, the corn starch, titanium dioxide, sodiumbisulfite, water and perfume are added with continued mixing. Theneutralization occurs over a period of about ten minutes and the mixingwith other materials lasts for an additional five minutes. At the end ofthe mixing, the temperature of the paste resulting is about 55 C.Because this temperature is considered too high at which to addheat-sensitive enzyme to the formulation, the paste is removed from thesigma blade mixer and is cooled, utilizing a heat exchanger, to atemperature of about 40 C., after which it is returned to the sigmablade mixer and the Protease Alcalase enzyme is added. If desired, suchaddition may be in the presence of some of the water of the formula, topromote better dispersion.

After complete mixing of the formula ingredients, which takes about anadditional five minutes, the paste is discharged to a mill. wherein itis milled to a chip or ribbon about 0.18 mm. thick. The milled detergentcomposition is then fed to a plodder, equipped with a vacuum connectionto prevent entrapment of air in the bar, and, using a nozzle plate at atemperature of about 60 C., composition is plodded at a pressure ofabout 14 kg./sq. cm. into a continuous bar of rounded rectangularcrosssection. The bar is cut to lengths and is pressed in a conventionalfour pocket automatic soap press at a pressure of about 21 kg./sq. cm.,after which the detergent bars are Wrapped and packed, ready forshipment to warehouses or retail stores.

The enzymatic detergent bars produced contain about 31% of the sodiumalkyl aryl sulfonate detergent, 17.5% of sodium carbonate, 7.5% ofsodium bicarbonate, 26.4% of corn starch, 13.9% of moisture, 1% ofsodium sulfate and 1% of free acid. The bars produced are of a desirablelight color and of good perfume aroma. They are hard enough so that theycan be handled and shipped without distortion and yet, dissolve in waterat a satisfactory rate, neither so fast as to smear and becomegelatinous nor so slow as to be difficult to employ in the treatment ofstained or dirty sections of laundry to be washed.

The detergent bars are tested for useful washing and stain-removingactivity by actual use tests on stained and dirty laundry and by othertests on intentionally stained cloths. In the laundry tests, the dirtyor stained laundry items are first wet with warm water, at about 40 C.,which is then drained or wrung out to leave the laundry damp. Then,dirty or stained sections are ru bed with he enzymatic detergent bar,producing a rather concentrated detergent and enzyme deposit in contactwith the dirt or stain. Yet, there is sufiicient water to promote theworking of the enzyme on the proteinaceous or other organic bondingagent which holds the dirt or stain to the textile. After about aminutes rubbing of the detergent bar constituents on the stains or dirtysections, they are left in this condition, with the concentration of barconstituents being about 5% on the average over the period of standing.Alternatively, more Water may be added and a more dilute soak, at aconcentration from about 0.05 to about 1%, may be used. Soaking lastsfor about 6 to 24 hours, after which the laundry is washed, using, ifdesired, more detergent bar constituents plus the previous wash water.Such washing takes place at about 70 C. and is effected in an automaticwashing machine, wherein the concentration of the enzymatic detergentcomposition is about 0.2% and the pH is about 9.

The washed laundry is noticeably cleaner and stains are removed to asignificantly better extent than when a similar laundry is washed in thesame manner, utilizing a bar containing no enzyme additive. Also, it isnoted that the perfume and color of the enzymatic detergent bar are verygood, despite storage under high temperature and high humidityconditions for periods as long as six months. In this respect, theenzyme appears to stabilize the perfume better in the experimental barthan in the control bar. Similar results are obtained when theexperimentally stained cloths are washed by the same techniques. Thestains are either completely or substantially removed.

Additional enzymatic detergent bars are made wherein minor proportions,0.05 to 1.0% of optical brighteners of the cotton and amide-polyesterbrightener classes, previously described in the specification, areincluded in the formula in place of a similar proportion of corn starch.Such products, when used according to the washing techniques describedpreviously, remove stains and dirt and also brighten the laundry so asto make any small signs of stains still present less apparent. In otherexperiments, pentasodium tripolyphosphate granules, colored with blueand green dyes, are mixed in with the milled enzymatic detergentcomposition before plodding and, using a total proportion of about 0.7%of such granules (which also contain minor proportions of dextrose). Aspeckled and somewhat marbleized detergent bar appearance is obtained,which distinctively identifies the enzymatic product to a consumer.

In similar manner, other synthetic or organic detergents are employedinstead of the one described above and in preferred compositions, thesynthetic organic detergent is a linear tridecyl benzene sulfonate,sodium salt. Nevertheless, instead of or in addition to such anionicdetergents, there may be used others, such as sodium monoglyceridesulfate, sodium lauryl alcohol sulfate, ammonium higher olefinsulfonates, Pluronics and Miranols. With respect to the builder salts,pentasodium tripolyphosphate, tetrasodium pyrophosphate and NTA can beadded to or substituted for the carbonate or bicarbonate. Similarly,instead of corn starch or part thereof there may be used amylopectin,potato starch, amylose or similar binder, and amylases, glycolase,hydrolases, oxidases, reductases may be substituted for the proteolyticenzyme. The antioxidant, sodium bisulfite, may be omitted or otheradjuvants with similar properties may be used. The variations in the barformulas and changes in proportions Within the ranges previously givenresult in enzymatic detergent bars having similar good washing andstain-removing properties, providing that the materials employed and theproportions thereof present are Within the scopes of the previousdescriptions. Also, in such formulas, it is highly preferred that cornstarch be the binder used, with protease being the enzyme,

EXAMPLE 2 Percent Dodecyl benzene sulfonic acid, bleached 29.0 Soda ash,dense, fine 42.4 Corn starch 12.2 Sodium silicate, 495 B. (Na O:SiO=1:2.0) 10.0 Proteolytic enzyme (Protease Alcalase) 0.6 Water, deionized5.6 Perfume, citronella 0.2

Following the manner of Example 1, as modified for the differentingredients, the sulfonic acid is neutralized with the soda ash, in thepresence of the sodium silicate and water, corn starch and perfume areadded, after which the mix is cooled and the enzyme is added. Theproduct comprises about 27.5% of active detergent, 35.0% so diumbicarbonate, 6.6% of sodium carbonate, 11.1% of corn starch, 4.5% ofsodium silicate and 14.7% water.

When tested in the washing of laundry and in stain removal from cottoncloths, even after months of storage, the enzyme is noticeably activeand the enzymatic detergent bar removes stains noticeably better than acontrol bar containing no enzyme. When brighteners such as Tinopal LCS,Uvitex 82R and Uvitex SEC are employed, to the extent of a total assmall as 0.1% or 0.2%, the combined cleaning and brightening effects aresignificant improvements over similar bars not containing suchingredients. Also noted is the improved stability of the perfume of thebar, apparently due to the presence of the enzyme and/or the combinationof enzyme and corn starch in the formula. The color of the bar is goodand it is not darkened or otherwise degraded by the presence of enzymes,corn starch and water therein. The bar density is about 1.3 g./cc.,desirably light in weight, and it is non-tacky.

Similar bars may be made containing more or less moisture and differentproportions of the enzymes, binders and builder salts and the desiredadvantages are still obtainable. Among the enzymes which may be includedare those commercially supplied as Protease Alcalase, Novo Industri (1.5Anson units per gram minimum activity); Alcaline Protease, WallersteinCompany, Division of Travenol Laboratories, Inc. (180,000 PCA units pergram minimum activity); Maxatase 330,000, Charles Pfizer and Company,Inc., Chemical Division (330,000 Delft. units per gram minimumactivity); and Chase Protease M-223, Chase Chemical Company (1.5 Ansonunits per gram minimum activity).

Although the washing methods described in Example 1 are preferred meansof effecting the best stain removal, since they utilize an extensivesoaking period in contact with the enzymatic detergent bar, it is alsofound that ordinary rubbing and washing of stained and soiled laundrywith the bar is effective, even when no extensive soaking period isemployed intermediate the initial rubbing and the final washing steps.

EXAMPLE 3 The procedure of Example 1 is repeated with the exception thatthe anionic detergent is charged to the mixer as a neutral salt,together with a proportion of water equivalent to that obtained in heneutralization reaction. By utilizing the neutralized detergent, mixingcan be effected at a lower temperature, even at room temperature,although it is preferred to mix at about 40 C. to improve the plasticityof the product during processing, so that it can be milled, plodded andpressed easily.

When tested against specific stains, such as coffee, chocolate, blood,mustard, wine, ketchup and grass stains, on cotton, rayon, nylon andpolyester-nylon blends, such detergent bars are good cleaning andstainremoving agents. In modifications thereof, the proteolytic enzymeis replaced by amylase, oxidases, reductases, and esterases and each ofthese is also found to have good stain-removing action. It is notablethat the enzymes are 14 not degraded by the presence of the corn starch,moisture, perfume detergent and builder components and in fact thepresence of the binder appears to stabilize the enzyme.

The invention has been described with respect to various illustrationsand examples thereof but is not to be considered as specifically limitedby them because it is apparent that equivalents may be substituted toproduce composition, products, methods and uses within the spirit andscope of the invention.

What is claimed is:

1. A detergent bar which consists essentially of 0.5 to 5% of an enzymeselected from the group consisting of proteolytic enzyme, amylase,catalase, lipase, maltase, phosphatase and mixtures thereof, the majorproportion of which is proteolytic enzyme, in an effective proportionfor chemically converting hard to remove soils and stains on laundry toa more readily removable form, 10 to 40% of synthetic organic detergent,20 to 60% of a salt selected from the group consisting of alkali metalcarbonate, alkali metal bicarbonate, borax, alkali metal silicate,alkali metal phosphate, trisodium nitrilotriacetate, tetrasodiumethylene diamine tetraacetate, tetrapotassium ethylene diaminetetraacetate and trisodium ethylene diamine tetraacetate builder saltsand water soluble inorganic sulfate, bisulfate and sodium chloridefiller salts, 5 to 40% of a binding agent selected from the groupconsisting of starch, amylose, amylopectin, partially hydrolyzed starch,alginates, agar, guar gum, polyvinyl alcohol and sodium carboxymethylcellulose and 12 to 25% of water, all homogeneously combined in aformretaining, hard, non-tacky, readily soluble, effectively cleaningbar.

2. A detergent bar according to claim 1 in which the enzyme content isfrom 0.1 to 1% and from 70 to thereof is proteolytic enzyme so that thedetergent bar contains from 0.001 to 0.1 Anson unit/gram, 20 to 60% of abuilder or a mixture of builders is present and the binding agent isfrom 10 to 35% of the bar, with from 70 to 100% thereof being starch.

3. A detergent bar according to claim 1 in which the synthetic detergentis an anionic synthetic organic detergent, builder salt is present andthe binding agent includes a major proportion of starch.

4. A detergent bar according to claim 3 in which the enzyme content isfrom 0.1 to 1% and from 70 to 100% thereof is proteolytic enzyme so thatthe detergent bar contains from 0.001 to 0.1 Anson unit per gram, theanionic synthetic organic detergent is selected from the groupconsisting of sulfated and sulfonated detergents having an alkyl groupof 8 to 22 carbon atoms, the builder and filler salts are inorganicsodium salts and the binding agent is from 10 to 35% of the bar and 70to 100% thereof is starch.

5. A detergent bar according to claim 4 wherein the enzyme is aproteolytic enzyme or mixture thereof, the anionic synthetic organicdetergent is higher alkyl benzene sulfonate of 8 to 18 carbon atoms inthe alkyl group, the builder salt is from 25 to 55% of the bar and thebinding agent is starch.

6. A detergent bar according to claim 5 wherein the enzyme is subtilisinenzyme of 1-8 Anson units/gram and from 0.2 to 1% thereof is present,the anionic synthetic organic detergent is sodium higher alkyl benzenesulfonate wherein the higher alkyl is of 10 to 16 carbon atoms, thebuilder salt includes sodium carbonate and sodium bicarbonate and thebinding agent is corn starch.

7. A detergent bar according to claim 6 which is milled and plodded andin which the moisture content is from 12 to 17%.

8. A detergent bar according to claim 7 which contains about 28% ofsodium higher alkyl benzene sulfonate, 35% sodium bicarbonate, 7% sodiumcarbonate, 11% corn starch, 5% sodium silicate, 15% water and 0.6%proteolytic enzyme.

9. A detergent bar according to claim 7 which contains about 31% ofsodium alkyl benzene sulfonate detergent, 18% sodium carbonate, 8%sodium bicarbonate, 26% of corn starch, 14% of moisture and at least0.009 Anson unit/gram of protease.

10. A detergent bar according to claim 9 which contains from 0.5 to 1%of optical brightener and suflicient proportion of coloring material togive the bar a distinct speckled appearance to identify it to a consumeras an enzymatic detergent bar.

References Cited UNITED STATES PATENTS Okenfuss 252539 Austin et al.252-539 Jelinek et a1. 25289 X Roald et a1. 252132 X Siebert et a1.252---132 McCarty 252135 FOREIGN PATENTS Great Britain 252132 HERBERT B.GUYNN, Primary Examiner U.S. c1. X.R.

25289, 174, 531, 532, 535, 546, DIG. 12, DIG. 16

